have a long time history of purpose-built automobiles using motorcycle engines. Combine a powerful enough engine with a light enough chassis, and the results can be very positive. But what about attaching a car engine to a bicycle? It’s a completely different ball game.
Fans of classic German engineering should recognize the power plant at the heart of this handcrafted construction chopper. It’s powered by an air-cooled four-cylinder boxer engine from a VW Beetle—and, as you can imagine, it takes a bit of ingenuity to put together.
It’s the work of Paul Clark—an Englishman whose hobby is building custom bikes for fun, not commercial gain. A lover of older and rarer brands, he has built up quite a few machines (and spare parts) collections over the years.
He told us, “I built a Dnieper chop and a JAP revving motor bike, as well as others. “These bikes aren’t shiny — far from that — and they’re not the kind of thing someone would pull over and say ‘I have one of those. They’re unique to me, my style, and I love them—but it’s great that other people appreciate them, too.”
Paul also likes to keep his projects low-cost, by using as many recycled and recycled parts as possible. This one started with an eBay search; £300 [about $379] The VW Beetle engine begs for a home. “Using the engine as a base, sitting on the floor of my workshop, I started to picture the finished bike in my head,” he said.
The first challenge was attaching the gearbox to the engine. Paul combined the Dnieper MT 650 transmission with the VW factory, through concentric flanges cut by waterjet from aluminum. The Dnieper clutch and flywheel have also been adapted to work in conjunction with the generator from the Kubota mini excavator.
Wassel Evolution carbs inhale through an Amal velocity stack, which is attached via a custom manifold. The zigzag exhaust pipes on either side of the engine may seem messy at first glance, but if you watch them carefully, you’ll be able to spot the piping of the custom stainless steel four-in-two exhaust system. Paul.
He added: “Once fitted, they would come dangerously close to the driver’s feet. “I didn’t want to wrap the exhaust or heat shield, so I opted to buy some knee-high boots to wear while riding; what we do to keep the aesthetic as we want it to be!”
With the basics out of the way, Paul set up a makeshift wheel alignment mold using a steel rod. The 16-inch rims are strapped to the Dnieper front and Honda Goldwing rear hubs, wrapped in fresh rubber and fitted to the lugs, along with the engine and transmission.
Starting with a part of the 1983 Honda Goldwing frame, Paul built the frame using spare pieces of tubing and a broom handle (yes, broom handle). The final frame is welded from steel pipe, again purchased from eBay, with a fork and fork from a Yamaha XJR1300 up front. The frame’s 50mm stainless steel top tube also acts as an air reservoir, for TC Bros’ ‘Air Ride’ system that sits under the slim chopper saddle.
“I think a saddle always looks better when it’s as close to the tire as possible, especially without the rear fender,” says Paul. I realized early on that it would be nice to have a chair that could be raised and lowered—but I didn’t want springs, so I opted for an airbag. It looks great in parking and is really comfortable to drive.”
A small 12 V air compressor ‘charges’ the top frame rail to about 40 PSI, which is enough to get the seat up and down about four times. If you look closely, you’ll spot a small air pressure gauge mounted right in front of the seat.
If the tank looks familiar, that’s because it’s from a Triumph Bonneville. Paul cut and closed it to sit wider and adjusted it to fit his frame. Right in front of it is the custom steering wheel, with Big Port Beston-style grips, throttle, brake and clutch levers, among other things.
Paul didn’t like shiny new bikes, so the frames were blasted and galvanized, then re-washed with gun stock paint and kitchen polish. That gave it an age-old molded look that matched the engine. First Choice Body Shop handles the red paint job, Central Wheel Components does the powder coating for Paul, and Brimscombe Platers handles all the polishing and plating.
In the final finishing step, Whiteway Craft Foundry built a small battery box that doubles as the generator stand. The fact that it looks a bit like an old VW bus is no coincidence.
As the project neared its end, Paul pondered whether his 132-pound frame could boot (yes, he chose to warm up) the stout VW boxer. “Yes, it has started — what a relief,” he quips. “It’s actually pretty easy to get through.”
Almost ready for his first test run, Paul then hit the biggest hurdle of the project. “I am a bit reclusive when it comes to construction,” he explains, “but advice on the odd technical details is always available from my oldest friend, Neil Baxter. One evening he came in for a cup of tea and casually said, ‘are you sure the rear wheel won’t go backwards with the axle on that side of the wheel?’”
“The propeller shaft is very tight and there is no room to change anything. We tried it, and to my shock and horror, the wheel was running in reverse! I was so depressed that I almost canceled the entire project—but with some encouragement, it was a case of solving this unforeseen problem.”
In the end, Paul had to remove the Goldwing’s bevel box and rear wheel, and replace them with a drive, and the Dnieper’s final axle was replaced. With a custom steel case on the final drive, the whole arrangement just fits the frame—but the important thing is that it fits. Two weeks later, the VW bike was ready for a test run.
Paul said: “I walked 20 feet, and it died. “A burnt coil seems to be the problem. After two more coils, it turned out that the Lithium battery wouldn’t work with the generator and replacing it with a small gel battery solved the problem.”
Finally on the road, Paul happily reports that the bike pulls very hard, reaching a top speed of around 60 mph. But since the Dnieper gearbox has four forward and one reverse, he can modify it to add a fifth gear.
“It’s not fun when you spend hours building a bike, only to find that it has one forward and four reverse gears. Having to cut a newly built wheel, repaint, and repaint is extremely frustrating. That particular problem almost solved it for me—but I’m glad it’s solved and the bike is done.”
“The car has its own logo, which is the reverse VW; the W at the top with the V at the bottom, as a reminder to check for such things much earlier in the next build. It’s also called ‘Bootsy’, a reminder to me to put on my new very high boots unless I want to burn my pants.
Images of, and thanks to, Del Hickey
